Hunter's knee gave out Friday in a noncontact drill, sending in motion the 49ers' task to find Frank Gore's top understudy, a role Hunter has mostly held since 2011.

The candidates are appealing: LaMichael James, who's had a quiet career since leaving as Oregon's rushing king; Carlos Hyde, a second-round pick in May who Baalke says is already "flashing" in camp; and, Marcus Lattimore, who's still a mystery because of a reconstructed knee.

"To have him go down is definitely going to hurt us," fullback Bruce Miller said of Hunter. "But it's an opportunity for guys to step up. We'll kind of use that to push through the season and do it for Kendall."

Hunter's roommate at camp is cornerback Chris Culliver, who's coming off an ACL tear from last training camp and sympathized with his fallen teammate.

"The only word I can describe it is 'devastating,' " Culliver said. "It's so easy to do that, to mess something up like that. But it's so hard to come back."

The 49ers at least have nice options to replace Hunter, to which offensive coordinator Greg Roman thanked the front office and scouting department. Rather than single out who's the "next man up," Roman noted that it's "not necessarily one person."

Advertisement

James, a 2012 second-round pick, went from potential trade bait to Saturday's No. 2 tailback, albeit in bittersweet fashion since Hunter is one of his best friends.

"You've just got to try to play for him," James said. "I've got to go compete, and when I feel I can't give anymore, I've got to give a little more for him, too."

James' first significant action in the pros came when Hunter tore an Achilles in November 2012.

There's one more running back to consider, and that's former practice-squad player Jewel Hampton, who's off to such a good start at camp that Baalke named him first in listing James' competitors.

As deep as the unit appears, Gore is still the workhorse entering his 10th season. Miller told Gore on Friday that he looks in midseason form. Gore certainly wants to remain the offense's catalyst and isn't bequeathing his carries yet.

"I'm here. I'm still here. So why not?" Gore said when he reported to camp Wednesday.

Baalke would not discuss guard Alex Boone's holdout, stating that any talks about the impasse (or daily $30,000 fines) will remain private between the player and team. Joe Looney has been taking first-team snaps in place of Boone, and Baalke said the 49ers are "very confident" Looney can succeed there.

Any NFL discipline of Aldon Smith is expected to be made before the regular season and perhaps before the Aug. 7 exhibition opener, Baalke said. No date has been announced for when Smith will meet with commissioner Roger Goodell, who has spoken with team owner Jed York on the matter. As for the 11 work-release days Smith must serve as part of his July 18 court sentence, Baalke said those Monday dates take precedence for Smith if they coincide with any 49ers workload.

Baalke wants to extend pending free agents Michael Crabtree and Mike Iupati but said contract negotiations must stop "at some point" so the players can focus on playing. Vernon Davis was deemed an "integral" part of the 49ers' plans, but Baalke wouldn't discuss Davis' recent contract wishes.

No noticeable casualties emerged from the first padded practice of camp, which was highlighted by Colin Kaepernick (completed last seven passes), Tramaine Brock (day's only interception) and Crabtree (one-handed catch).